A high performance liquid chromatograph time-of-flight (LC-TOF) mass spectrometer will be purchased and used for accurate mass measurements in support of the research of a multidisciplinary group of NIH-funded users (including two multi-investigator center projects). In addition, minor users and new users at the University of Illinois at Chicago as well as nearby Northwestern University and the University of Chicago will be provided access to the proposed LC-TOF mass spectrometer. The LC-TOF mass spectrometer will complement the capabilities of an existing JEOL GCMate mass spectrometer by providing accurate mass measurements using electrospray and/or atmospheric pressure chemical ionization (APCI). Electrospray, APCI, and HPLC are not available on the GCMate. In addition, the new LC-TOF system will provide combined accurate mass measurement with on- line HPLC separation, which is not currently available to this user group, as well as higher throughput than our existing instrumentation. The LC-TOF mass spectrometer will be located within a campus-wide shared instrumentation laboratory called the Research Resources Center (RRC). The RRC is a centralized campus instrumentation facility that has been in operation for over 50 years and is under the oversight of the Vice Chancellor for Research. Access to the instrument by new and continuing users on and off campus will be assured through the administrative oversight of an advisory committee appointed by the RRC. In anticipation of the expansion of our accurate mass measurement service, the RRC recently hired a Ph.D. level mass spectrometrist to oversee the operation of the new LC-TOF mass spectrometer. This new staff position is committed for at least the useful lifetime of the proposed LC-TOF mass spectrometer. In support of this and other Ph.D.-level mass spectrometrists at the RRC, the P.I. (who has more than 20 years of experience managing mass spectrometry facilities) provides oversight to the RRC and advice to the users of the RRC Mass Spectrometry Laboratory. These on-going personnel commitments represent substantial support by the university. User fees (determined by the advisory committee) will be collected to defray the costs of consumable supplies and repairs. Overall, the proposed LC-TOF mass spectrometer will expand our capacity to provide accurate mass measurements to natural product chemists and synthetic organic chemists in the user community who rely upon rapid analyses of their compounds in order to advance with their NIH-funded research programs [unreadable] [unreadable] [unreadable]